Side airbag device and method of sewing side airbag

ABSTRACT

A side airbag device has: a side airbag that inflates and expands at a time of a side collision, and that has a lower chamber (high pressure chamber), and an upper chamber (low pressure chamber), the high pressure chamber and the low pressure chamber being formed by base cloths (a lower base cloth, an upper base cloth) that are respectively separate bodies; an inflator; a partitioning wall that is formed by a portion of the lower base cloth, and that divides the lower chamber and the upper chamber; and a check valve that is provided at a partial region of the partitioning wall, and that is provided convexly toward the lower chamber side when the side airbag is not inflated, and that permits flowing of the gas for inflation from the upper chamber side to the lower chamber side, and restricts flowing of gas in a direction opposite thereto.

TECHNICAL FIELD

The present invention relates to a side airbag device and a method ofsewing a side airbag.

BACKGROUND ART

There is disclosed an airbag cutting for an airbag having pluralportions of a passenger protecting device for an automobile, the airbagcutting having at least two mutually-overlapping airbag portions thatcan be connected along the outer edge portions in order to form theairbag, and can be connected together at an overlapping region, and, ina state in which the airbag is inflated, the overlapping region forms aborder surface between two chambers of the airbag (see Patent Document1).

PRIOR ART DOCUMENTS Patent Documents

[Patent Document 1] Japanese Patent Application National Publication No.2005-531451

SUMMARY OF INVENTION Technical Problem

However, in the above-described conventional example, the sewn length islong, and there is room for improvement in terms of mass-productivityand cost.

In view of the above-described circumstances, an object of the presentinvention is to reduce costs required for sewing a side airbag, and todevise smaller size and lighter weight of a package that is formed by aside airbag being folded-up.

Solution to Problem

A first aspect of the present invention has: a side airbag that inflatesand expands at a time of a side collision, and that has a high pressurechamber that becomes a high pressure side at a time of inflation andexpansion, and a low pressure chamber that becomes a lower pressure thanthe high pressure chamber, the high pressure chamber and the lowpressure chamber being formed by base cloths that are respectivelyseparate bodies; an inflator that supplies gas for inflation into theside airbag; a partitioning wall that is formed by a portion of a basecloth that forms the high pressure chamber, and that divides the highpressure chamber and the low pressure chamber; and a check valve that isprovided at a partial region of the partitioning wall, and that isprovided convexly toward the high pressure chamber side when the sideairbag is not inflated, and that permits flowing of the gas forinflation from the low pressure chamber side to the high pressurechamber side, and restricts flowing of gas in a direction oppositethereto.

In the side airbag device relating to the first aspect, the side airbaghas a high pressure chamber that becomes a high pressure side at a timeof inflation and expansion, and a low pressure chamber that becomes alower pressure than the high pressure chamber, and the high pressurechamber and the low pressure chamber are divided by the partitioningwall. The high pressure chamber and the low pressure chamber are formedby base cloths that are respectively separate bodies, and thepartitioning wall is formed by a portion of the base cloth that formsthe high pressure chamber. Therefore, as compared with a structure inwhich the base cloth and the partitioning wall are made to be separatebodies, costs required for sewing the side airbag can be reduced.

Further, although the internal pressure of the high pressure chamber ismaintained by the check valve, this check valve is provided at a partialregion of the partitioning wall. Therefore, as compared with a structurein which the check valve is provided separately, costs required forsewing the side airbag is reduced, and smaller size and lighter weightof the package formed by folding-up the side airbag can be devised.

Moreover, at the time of a side collision, the inflator operates, andthe gas for inflation that is jetted-out from the inflator is suppliedto the high pressure chamber and the low pressure chamber. At this time,the check valve that is provided at a partitioning wall is providedconvexly toward the high pressure chamber side when the side airbag isnot inflated. Therefore, flowing of the gas for inflation from the lowpressure chamber side to the high pressure chamber side is permitted,and flowing of gas in the direction opposite thereto is restricted.Namely, when jetting-out of the gas from the inflator ends, gas attemptsto flow backward from the high pressure chamber to the low pressurechamber, but because the check valve restricts this flow of gas, theinternal pressure of the high pressure chamber can be maintained in ahigh pressure state over a longer time.

In a second aspect of the present invention, in the side airbag devicerelating to the first aspect, the base cloth that forms the highpressure chamber is folded in two convexly toward the high pressurechamber side at a region that becomes a central portion of thepartitioning wall, and is further folded-over respectively toward a bagouter side and the high pressure chamber side at both end portions in abag thickness direction of a region that becomes the partitioning wall,and end edges that are positioned at a peripheral edge portion of thehigh pressure chamber are sewn together.

In the side airbag device relating to the second aspect, the base cloththat forms the high pressure chamber is folded in two convexly towardthe high pressure chamber side at a region that becomes a centralportion of the partitioning wall, and therefore, it is easy to make apartial region of the partitioning wall be the check valve. Further, thebase cloth that forms the high pressure chamber is folded-overrespectively toward a bag outer side and the high pressure chamber sideat both end portions in a bag thickness direction of a region thatbecomes the partitioning wall, and end edges are sewn together at aperipheral edge portion of the high pressure chamber. Therefore, sewingof the side airbag can be lessened. Thus, the mass-productivity of theside airbag can be improved.

In a third aspect of the present invention, in the side airbag devicerelating to the first aspect, the base cloth that forms the highpressure chamber is folded in two at a bottom portion of the highpressure chamber, and is folded-over respectively toward a bag innerside and the high pressure chamber side at both end portions in a bagthickness direction of a region that becomes the partitioning wall, andend edges that are positioned at a central portion of the partitioningwall are sewn together, and end edges that are positioned at aperipheral edge portion of the high pressure chamber are sewn together.

In the side airbag device relating to the third aspect, the base cloththat forms the high pressure chamber is folded in two at a bottomportion of the high pressure chamber, and is folded-over respectivelytoward a bag inner side and the high pressure chamber side at both endportions in a bag thickness direction of a region that becomes thepartitioning wall, and end edges are sewn together at a region thatbecomes a central portion of the partitioning wall. Therefore, it iseasy to make a partial region of the partitioning wall be the checkvalve. Further, because the high pressure chamber is formed by sewingtogether end edges of the base cloth, that are positioned at theperipheral edge portion of the high pressure chamber, at the base cloththat forms the high pressure chamber, sewing of the side airbag can belessened. Therefore, the mass-productivity of the side airbag can beimproved.

In a fourth aspect of the present invention, in the side airbag devicerelating to the second or third aspect, at the side airbag in aninflated and expanded state, the high pressure chamber is a lowerchamber that corresponds to a waist portion of a passenger seated in avehicle seat, and the low pressure chamber is an upper chamber thatcorresponds to at least one of a chest portion or a shoulder portion ofthe passenger.

In the side airbag relating to the fourth aspect, at the side airbag inan inflated and expanded state, the high pressure chamber is a lowerchamber that corresponds to a waist portion of a passenger seated in avehicle seat, and the low pressure chamber is an upper chamber thatcorresponds to at least one of a chest portion or a shoulder portion ofthe passenger. Therefore, when the side airbag inflates and expands, thelower chamber becomes higher pressure than the upper chamber.Accordingly, the waist portion of the passenger seated in the vehicleseat can be restrained by the lower chamber that is relatively highpressure, and further, at least one of the chest portion and theshoulder portion of the passenger can be restrained by the upper chamberthat is relatively low pressure. Moreover, because the internal pressureof the lower chamber can be maintained over a longer time by the checkvalve, the passenger restraining performance at the time of a sidecollision can be improved more.

In a fifth aspect of the present invention, in the side airbag devicerelating to the second aspect or the third aspect, at the side airbag inan inflated and expanded state, the high pressure chamber is a lowerchamber that corresponds to a waist portion of a passenger seated in avehicle seat and an upper chamber that corresponds to a shoulder portionof the passenger, and the low pressure chamber is an intermediatechamber that is positioned between the upper chamber and the lowerchamber and corresponds to a chest portion of the passenger.

In the side airbag device relating to the fifth aspect, at the sideairbag in an inflated and expanded state, the high pressure chamber is alower chamber that corresponds to a waist portion of a passenger seatedin a vehicle seat and an upper chamber that corresponds to a shoulderportion of the passenger, and the low pressure chamber is anintermediate chamber that is positioned between the upper chamber andthe lower chamber and corresponds to a chest portion of the passenger.Therefore, when the side airbag inflates and expands, the lower chamberand the upper chamber become higher pressure than the intermediatechamber. Accordingly, the waist portion of the passenger seated in thevehicle seat can be restrained by the lower chamber that is relativelyhigh pressure, and the shoulder portion of the passenger can berestrained by the upper chamber that similarly is relatively highpressure, and further, the chest portion of the passenger can berestrained by the intermediate chamber that is relatively low pressure.Moreover, because the internal pressures of the lower chamber and theupper chamber can be maintained over a longer time by the check valve,the passenger restraining performance at the time of a side collisioncan be improved more.

A sixth aspect of the present invention has, in the side airbag devicerelating to the fourth aspect, a diffuser that guides the gas forinflation mainly to the lower chamber side, and also guides the gas forinflation to the upper chamber side, wherein the diffuser has a mainopening portion that opens to the lower chamber side, and an auxiliaryopening portion that opens to the upper chamber side.

In the side airbag device relating to the sixth aspect, when the sideairbag inflates and expands, the gas for inflation that is supplied fromthe inflator is guided mainly to the lower chamber side through the mainopening portion of the diffuser, and is guided and distributed also tothe upper chamber side through the auxiliary opening portion. Due to thesimple structure of adding such a diffuser, the lower chamber can beinflated and expanded rapidly and stably, and the upper chamber can beinflated and expanded stably.

A seventh aspect of the present invention has, in the side airbag devicerelating to the fifth aspect, a diffuser that guides the gas forinflation mainly to the lower chamber side and the upper chamber side,and also guides the gas for inflation to the intermediate chamber side,wherein the diffuser has main opening portions that open to the lowerchamber side and the upper chamber side, respectively, and an auxiliaryopening portion that opens to the intermediate chamber side.

In the side airbag device relating to the seventh aspect, when the sideairbag inflates and expands, the gas for inflation that is supplied fromthe inflator is guided mainly to the lower chamber side and the upperchamber side through the main opening portions of the diffuser, and isguided and distributed to the intermediate chamber side through theauxiliary opening portion. Due to the simple structure of adding such adiffuser, the lower chamber and the upper chamber can respectively beinflated and expanded rapidly and stably, and the intermediate chambercan be inflated and expanded stably.

In an eighth aspect of the present invention, in the side airbag devicerelating to the seventh aspect, the main opening portions of thediffuser are disposed so as to pass through at least one of the checkvalve of the lower chamber side and the check valve of the upper chamberside.

In the side airbag device relating to the eighth aspect, because themain opening portions of the diffuser are disposed so as to pass throughat least one of the check valve of the lower chamber side and the checkvalve of the upper chamber side, the gas for inflation that is suppliedfrom the inflator can be guided more directly to both of or one of thelower chamber and the upper chamber. Therefore, both of or one of thelower chamber and the upper chamber be inflated and expanded morerapidly and stably.

In a ninth aspect of the present invention, in the side airbag devicerelating to any one aspect of the fifth, seventh or eighth aspects, abag thickness of the lower chamber is set to be thicker than a bagthickness of the upper chamber, in an inflated and expanded state of theside airbag.

In the side airbag device relating to the ninth aspect, because the bagthickness of the lower chamber that corresponds to the waist portion ofthe passenger is set to be thicker than the bag thickness of the upperchamber that corresponds to the shoulder portion of the passenger, therestraining force with respect to the waist portion can be generated atan earlier timing than the shoulder portion, at the time when thepassenger is restrained by the side airbag. Due thereto, the respectiveportions of the upper body of the passenger can respectively berestrained at appropriate timings and appropriate restraining forces.

In a tenth aspect of the present invention, in the side airbag devicerelating to any one aspect of the sixth through ninth aspects, a basecloth that forms the diffuser is sewn together with a base cloth thatforms the low pressure chamber at at least a peripheral edge portion ofthe low pressure chamber, and is formed in a form of a tube.

In the side airbag device relating to the tenth aspect, the base cloththat forms the diffuser is sewn together with the base cloth that formsthe low pressure chamber, at at least a peripheral edge portion of thelow pressure chamber, and is formed in the form of a tube. Therefore,even if a diffuser is provided, the increase in cost required for sewingthe side airbag can be suppressed.

In an eleventh aspect of the present invention, in the side airbagdevice relating to any one aspect of the fifth or seventh through ninthaspects, an end edge, that runs along a length direction of thediffuser, at a base cloth that forms the intermediate chamber is sewn toa side portion of the diffuser, such that an overlapping region of thebase cloth and the diffuser is reduced.

In the side airbag device relating to the eleventh aspect, because anend edge, that runs along a length direction of the diffuser, at a basecloth that forms the intermediate chamber is sewn to a side portion ofthe diffuser such that an overlapping region of the base cloth and thediffuser is reduced, the surface area of the base cloth that forms theintermediate chamber can be reduced. Therefore, the materials cost ofthe side airbag is reduced, and even smaller size and lighter weight ofthe package formed by folding-up the side airbag can be devised.

A twelfth aspect of the present invention is a method of sewing a sideairbag, the side airbag having a high pressure chamber that becomes ahigh pressure side at a time of inflation and expansion, and a lowpressure chamber that becomes a lower pressure than the high pressurechamber, and in which the high pressure chamber and the low pressurechamber are formed by base cloths, that are respectively separatebodies, and are divided by a partitioning wall, and in which thepartitioning wall is formed by a portion of a base cloth that forms thehigh pressure chamber, the method comprising: a step of forming, at apartial region of the partitioning wall, a check valve that permitsflowing of the gas for inflation from the low pressure chamber side tothe high pressure chamber side, and restricts flowing of gas in adirection opposite thereto.

In the method of sewing a side airbag relating to the twelfth aspect,because the partitioning wall is formed by a portion of the base cloththat forms the high pressure chamber, as compared with a structure inwhich the base cloth and the partitioning wall are made to be separatebodies, costs required for sewing the side airbag can be reduced.Further, as compared with a structure in which the check valve isprovided separately, costs required for sewing the side airbag isreduced, and smaller size and lighter weight of the package formed byfolding-up the side airbag can be devised.

A thirteenth aspect of the present invention further comprises, in themethod of sewing a side airbag relating to the twelfth aspect, a step offolding the base cloth that forms the high pressure chamber in twoconvexly toward the high pressure chamber side at a region that becomesa central portion of the partitioning wall, and sewing both end portionsin a bag thickness direction of a region that becomes the partitioningwall to a base cloth that forms the low pressure chamber; and a step offolding-over the base cloth that forms the high pressure chamber,respectively toward a bag outer side and the high pressure chamber sideat both end portions in the bag thickness direction of the region thatbecomes the partitioning wall, and, at a peripheral edge portion of thehigh pressure chamber, sewing together end edges of the base cloth thatforms the high pressure chamber, and, at a peripheral edge portion ofthe low pressure chamber, sewing together end edges of the base cloththat forms the low pressure chamber.

In the method of sewing a side airbag relating to the thirteenth aspect,by folding the base cloth that forms the high pressure chamber in twoconvexly toward the high pressure chamber side at a region that becomesa central portion of the partitioning wall, and sewing both end portionsin the bag thickness direction of a region that becomes the partitioningwall to a base cloth that forms the low pressure chamber, the base cloththat forms the high pressure chamber and the base cloth that forms thelow pressure chamber are joined, and the partitioning wall is formed ata portion of the base cloth that forms the high pressure chamber.Further, the high pressure chamber and the low pressure chamber can beformed by sewing of a single time by folding-over the base cloth, thatforms the high pressure chamber, respectively toward a bag outer sideand the high pressure chamber side at both end portions in the bagthickness direction of the region that becomes the partitioning wall,and sewing together end edges of the respective base cloths at aperipheral edge portion of the high pressure chamber and a peripheraledge portion of the low pressure chamber. Therefore, costs required forsewing the side airbag can be further reduced.

A fourteenth aspect of the present invention has, in the method ofsewing a side airbag relating to the twelfth aspect, a step of foldingthe base cloth that forms the high pressure chamber in two at a bottomportion of the high pressure chamber, and sewing both end portions in abag thickness direction of a region that becomes the partitioning wall,at the base cloth, to a base cloth that forms the low pressure chamber;a step of folding-over the base cloth that forms the high pressurechamber, respectively toward a bag inner side and the high pressurechamber side from a position sewn with the base cloth that forms the lowpressure chamber, and sewing end edges thereof together excluding thepartial region that becomes the check valve; and, at a peripheral edgeportion of the high pressure chamber, sewing together end edges of thebase cloth that forms the high pressure chamber, and, at a peripheraledge portion of the low pressure chamber, sewing together end edges ofthe base cloth that forms the low pressure chamber.

In the method of sewing a side airbag relating to the fourteenth aspect,by folding the base cloth, that forms the high pressure chamber, in twoat a bottom portion of the high pressure chamber, and sewing both endportions in the bag thickness direction of a region that becomes thepartitioning wall, at the base cloth, to a base cloth that forms the lowpressure chamber, the base cloth that forms the high pressure chamberand the base cloth that forms the low pressure chamber are joined, and aregion that becomes the partitioning wall is ensured at a portion of thebase cloth that forms the high pressure chamber.

Further, the partitioning wall is formed by folding-over the base cloththat forms the high pressure chamber, respectively toward a bag innerside and the high pressure chamber side from a position sewn with thebase cloth that forms the low pressure chamber, and sewing end edgesthereof together excluding the partial region that becomes the checkvalve.

Moreover, the high pressure chamber and the low pressure chamber can beformed by sewing of a single time by, at a peripheral edge portion ofthe high pressure chamber, sewing together end edges of the base cloththat forms the high pressure chamber, and, at a peripheral edge portionof the low pressure chamber, sewing together end edges of the base cloththat forms the low pressure chamber. Therefore, costs required forsewing the side airbag can be further reduced.

A fifteenth aspect of the present invention has: a side airbag thatinflates and expands at a time of a side collision and is found bysewing peripheral edge portions of a facing base cloth, and that has aninitially inflated portion to which gas for inflation is supplied at aninitial stage of inflation and expansion, a lower chamber that becomes ahigh pressure side at a time of inflation and expansion and correspondsto a waist portion of a passenger seated in a vehicle seat, an upperchamber that becomes a high pressure side at a time of inflation andexpansion and corresponds to a shoulder portion of the passenger, and anintermediate chamber that becomes a lower pressure than the lowerchamber and the upper chamber at a time of inflation and expansion andcorresponds to a chest portion of the passenger; an inflator thatsupplies gas for inflation to the initially inflated portion of the sideairbag; a lower partitioning wall that is provided within the sideairbag, and that divides the lower chamber and the intermediate chamber,and divides the lower chamber and the initially inflated portion; alower check valve that is provided at a partial region of the lowerpartitioning wall, and that is provided convexly toward the lowerchamber side when the side airbag is not inflated, and that permitsflowing of the gas for inflation from the initially inflated portionside to the lower chamber side, and restricts flowing of gas in adirection opposite thereto; an upper partitioning wall that is providedwithin the side airbag, and that divides the upper chamber and theintermediate chamber, and divides the upper chamber and the initiallyinflated portion; an upper check valve that is provided at a partialregion of the upper partitioning wall, and that is provided convexlytoward the upper chamber side when the side airbag is not inflated, andthat permits flowing of the gas for inflation from the initiallyinflated portion side to the upper chamber side, and restricts flowingof gas in a direction opposite thereto; and an intermediate partitioningwall that is provided within the side airbag so as to divide theinitially inflated portion and the intermediate chamber, and in which isprovided an air hole that permits inflow of gas from the initiallyinflated portion to the intermediate chamber.

In the side airbag device relating to the fifteenth aspect, because thelower check valve is provided at a partial region of the lowerpartitioning wall and the upper check valve is provided at a partialregion of the upper partitioning wall, as compared with a structure inwhich the respective check valves are provided separately from therespective partitioning walls, costs required for sewing the side airbagis reduced, and smaller size and lighter weight of the package formed byfolding-up the side airbag can be devised.

Further, at the time of a side collision, the inflator operates, and gasfor inflation that is jetted-out from the inflator is first supplied tothe initially inflated portion. This gas is further supplied from theinitially inflated portion through the lower check valve to the lowerchamber, and is supplied through the upper check valve to the upperchamber, and is supplied through the air hole of the intermediatepartitioning wall to the intermediate chamber. When the jetting-out ofgas from the inflator ends, gas attempts to flow backward from the lowerchamber and the upper chamber to the initially inflated portion, butbecause the lower check valve and the upper check valve restrict thisflow of gas, the internal pressure of the lower chamber and the internalpressure of the upper chamber can respectively be maintained in highpressure states.

On the other hand, because the backward flow of gas from theintermediate chamber to the initially inflated portion is permitted, theinternal pressure of the intermediate chamber can be made to berelatively low pressure. Therefore, the chest portion of the passengercan be restrained appropriately by the intermediate chamber.

Advantageous Effects of Invention

As described above, in accordance with the side airbag device relatingto the first aspect of the present invention, the excellent effects areobtained that costs required for sewing the side airbag is reduced, andsmaller size and lighter weight of the package formed by folding-up theside airbag can be devised.

In accordance with the side airbag device relating to the second aspect,the excellent effect is obtained that costs required for sewing the sideairbag can be reduced as compared with a structure in which the basecloth and the partitioning wall are made to be separate bodies.

In accordance with the side airbag device relating to the third aspect,sewing of the side airbag can be lessened. Therefore, the excellenteffect that the mass-productivity of the side airbag can be improved isobtained.

In accordance with the side airbag device relating to the fourth aspect,the excellent effects are obtained that the waist portion of thepassenger seated in the vehicle seat can be restrained by the lowerchamber that is relatively high pressure, and further, at least one ofthe chest portion or the shoulder portion of the passenger can berestrained by the upper chamber that is relatively low pressure.

In accordance with the side airbag device relating to the fifth aspect,the excellent effects are obtained that the waist portion of thepassenger seated in the vehicle seat can be restrained by the lowerchamber that is relatively high pressure, and the shoulder portion ofthe passenger can be restrained by the upper chamber that similarly isrelatively high pressure, and moreover, the chest portion of thepassenger can be restrained by the intermediate chamber that isrelatively low pressure.

In accordance with the side airbag device relating to the sixth aspect,the excellent effects are obtained that, by the simple structure ofadding the diffuser, the lower chamber is inflated and expanded rapidlyand stably, and the upper chamber can be inflated and expanded stably.

In accordance with the side airbag device relating to the seventhaspect, the excellent effects are obtained that, by the simple structureof adding the diffuser, the lower chamber and the upper chamber arerespectively inflated and expanded rapidly and stably, and theintermediate chamber can be inflated and expanded stably.

In accordance with the side airbag device relating to the eighth aspect,the excellent effect is obtained that both or one of the lower chamberand the upper chamber can respectively be inflated and expanded morerapidly and stably.

In accordance with the side airbag device relating to the ninth aspect,the excellent effect is obtained that the respective portions of theupper body of the passenger can respectively be restrained atappropriate timings and by appropriate restraining forces.

In accordance with the side airbag device relating to the tenth aspect,the excellent effect is obtained that, even if a diffuser is provided,the increase in costs required for sewing the side airbag can besuppressed.

In accordance with the side airbag device relating to the eleventhaspect, the excellent effects are obtained that the materials cost ofthe side airbag is reduced, and even smaller size and lighter weight ofthe package formed by folding-up the side airbag can be devised.

In accordance with the method of sewing a side airbag relating to thetwelfth aspect, the excellent effects are obtained that costs requiredfor sewing the side airbag is reduced, and smaller size and lighterweight of the package formed by folding-up the side airbag can bedevised.

In accordance with the method of sewing a side airbag relating to thethirteenth aspect, the excellent effect is obtained that costs requiredfor sewing the side airbag can be further reduced.

In accordance with the method of sewing a side airbag relating to thefourteenth aspect, the excellent effect is obtained that costs requiredfor sewing the side airbag can be further reduced.

In accordance with the side airbag device relating to the fifteenthaspect, the excellent effects are obtained that costs required forsewing the side airbag is reduced, and smaller size and lighter weightof the package formed by folding-up the side airbag can be devised.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 through FIG. 12 relate to a first embodiment, and FIG. 1 is aside view showing a state in which a side airbag is inflated andexpanded at the side of a passenger seated in a vehicle seat.

FIG. 2 is a side view showing a side airbag device.

FIG. 3 is a partial sectional perspective view showing the way offolding a lower base cloth.

FIG. 4 is a partial sectional perspective view showing a state in whicha sewn portion is provided at an adjacent region of a region thatbecomes a check valve, of a folded-in end edge of a partitioning wall.

FIG. 5 is a partial sectional perspective view showing the side airbagdevice in a completed state.

FIG. 6 is an enlarged sectional view seen in the direction of arrowsF6-F6 in FIG. 2, showing an example of the state of the partitioningwall when the side airbag is not inflated.

FIG. 7 is an enlarged sectional view seen in the direction of arrowsF7-F7 in FIG. 2, showing an example of the state of the partitioningwall when the side airbag is inflated.

FIG. 8 is an enlarged sectional view seen in the direction of arrowsF8-F8 in FIG. 2, showing an example of the state of a vicinity of a sewnportion of the partitioning wall, when the side airbag is inflated andexpanded.

FIG. 9 is an enlarged sectional view seen in the direction of arrowsF9-F9 in FIG. 2, showing an example of the state of the partitioningwall and a diffuser at a time when gas, that is jetted-out from gasjetting-out portions of an inflator, flows into a lower chamber.

FIG. 10 is an enlarged sectional view seen in the direction of arrowsF10-F10 in FIG. 2, showing a state in which jetting-out of gas from theinflator has ended and the check valve has closed.

FIG. 11 is an enlarged sectional schematic view of main portions seen inthe direction of arrows F11-F11 in FIG. 2, showing an example ofinflated thicknesses of respective portions of the side airbag.

FIG. 12 is an enlarged sectional schematic view of main portions seen inthe direction of arrows F12-F12 in FIG. 2, showing another example ofinflated thicknesses of respective portions of the side airbag.

FIG. 13 through FIG. 18 relate to a second embodiment, and FIG. 13 is aside view showing a side airbag device.

FIG. 14 is an exploded perspective view of main portions showing theside airbag device.

FIG. 15 is an enlarged sectional view seen in the direction of arrowsF15-F15 in FIG. 13, showing an example of the state of the partitioningwall when the side airbag is inflated and expanded.

FIG. 16 is an enlarged sectional schematic view of main portions seen inthe direction of arrows F16-F16 in FIG. 13, showing an example of thestate of the partitioning wall in a vicinity of the check valve, whenthe side airbag is inflated and expanded.

FIG. 17 is an enlarged sectional view seen in the direction of arrowsF17-F17 in FIG. 13, showing an example of the state of the partitioningwall and the diffuser at a time when gas, that is jetted-out from thegas jetting-out portions of the inflator, flows into the lower chamber.

FIG. 18 is an enlarged sectional view seen in the direction of arrowsF18-F18 in FIG. 13, showing a state in which jetting-out of gas from theinflator has ended and the check valve has closed.

FIG. 19 through FIG. 21 relate to a third embodiment, and FIG. 19 is aside view showing a state in which the side airbag is inflated andexpanded at the side of a passenger seated in the vehicle seat.

FIG. 20 is a side view showing a side airbag device.

FIG. 21 is an exploded perspective view of main portions showing theside airbag device.

FIG. 22 through FIG. 24 relate to a fourth embodiment, and FIG. 22 is aside view showing a side airbag device.

FIG. 23 is an enlarged perspective view of main portions seen in thedirection of arrows F23-O-F23 in FIG. 22, showing an example of thestates of a lower partitioning wall, an upper partitioning wall, and thediffuser at a time when gas, that is jetted-out from the gas jetting-outportions of the inflator, flows into a lower chamber and an upperchamber.

FIG. 24 is a drawing showing a state in which jetting-out of gas fromthe inflator has ended, and a lower opening portion and an upper openingportion of the diffuser, and a lower check valve and an upper checkvalve, have closed.

FIG. 25 through FIG. 28 relate to a fifth embodiment, and FIG. 25 is aside view showing a side airbag device.

FIG. 26 is an exploded perspective view showing the side airbag device.

FIG. 27 is a sectional view seen in the direction of arrows F27-F27 inFIG. 26, showing the internal structure of the side airbag device.

FIG. 28 is a sectional view seen in the direction of arrows F28-F28 inFIG. 26, showing the internal structure of the side airbag device.

FIG. 29 through FIG. 35 relate to a sixth embodiment, and FIG. 29 is aside view showing a state in which the side airbag is inflated andexpanded at the side of a passenger seated in the vehicle seat.

FIG. 30 is a side view of a side airbag device.

FIG. 31 is an enlarged sectional view seen in the direction of arrowsF31-F31 in FIG. 30, showing an upper partitioning wall.

FIG. 32 is an enlarged sectional view showing a state in which an uppercheck valve has opened, and gas is flowing into an upper chamber from aninitially inflated portion.

FIG. 33 is an enlarged sectional view showing a state in which the uppercheck valve has closed.

FIG. 34 is an enlarged sectional view seen in the direction of arrowsF34-F34 in FIG. 30, showing a state in which the upper check valve hasopened, and gas is flowing into the upper chamber from the initiallyinflated portion.

FIG. 35 is an enlarged sectional view seen in the direction of arrowsF35-F35 in FIG. 30, showing a state in which the upper check valve hasclosed.

DESCRIPTION OF EMBODIMENTS First Embodiment

In FIG. 1, a side airbag device 10 relating to the present embodimentrelates to, for example, a side airbag device that is installed in theside portion of a seat back 14 at a vehicle seat 12, and has a sideairbag 16, an inflator 18, a partitioning wall 22, and a check valve 24.

In FIG. 1, FIG. 2, the side airbag 16 has a lower chamber 26 that is anexample of a high pressure chamber that becomes the high pressure sideat the time of inflation and expansion, and an upper chamber 28 that isan example of a low pressure chamber that becomes a lower pressure thanthe lower chamber 26, and the lower chamber 26 and the upper chamber 28are formed by base cloths that are respectively separate bodies. Thelower chamber 26 and the upper chamber 28 are formed so as to, at thetime of a side collision, receive a supply of gas for inflation, andrespectively inflate and expand at the side of a passenger 32 seated inthe vehicle seat 12.

The lower chamber 26 is formed from a lower base cloth 27 that is aseparate body from the upper chamber 28, and, at the side airbag 16 inthe inflated and expanded state, is the inflated portion that ispositioned at the vehicle lower side, and corresponds to a waist portion32W of the passenger 32 seated in the vehicle seat 12. As shown in FIG.3, the lower base cloth 27 that forms this lower chamber 26 is formedby, at a region that becomes the central portion of the partitioningwall 22, being folded in two convexly toward the lower chamber 26 side,i.e., the vehicle lower side, and further, at both end portions in thebag thickness direction of the region that becomes the partitioning wall22, i.e., at upper end portions 27U, being folded over respectivelytoward the outer sides (arrow D directions), and, as shown in FIG. 5,end edges 27C that become the peripheral edge portion of the lowerchamber 26 being sewn together (sewn portion S1). Of the lower basecloth 27, the region between the upper end portions 27U at the bothsides forms the partitioning wall 22. Note that, in order to improve theair-tightness of the lower chamber 26 that serves as the high pressurechamber, coating may be carried out on the inner surface of the lowerbase cloth 27.

The upper chamber 28 is formed by upper base cloths 29 that are separatebodies from the lower chamber 26, and, at the side airbag 16 in theinflated and expanded state, is the inflated portion that is positionedat the vehicle upper side, and corresponds to at least one of a chestportion 32C or a shoulder portion 32S of the passenger 32 seated in thevehicle seat 12. In the present embodiment, the upper chamber 28corresponds to both the chest portion 32C and the shoulder portion 32Sof the passenger 32, and also corresponds to an upper arm portion (notillustrated) and an abdomen portion 32A. As shown in FIG. 5, FIG. 6,this upper chamber 28 is formed by, for example, lower end portions 29Dof the pair of upper base cloths 29, that are positioned at the bagthickness direction both sides, being sewn (sewn portions S2) to theupper end portions 27U of the lower base cloth 27 that forms the lowerchamber 26, and end edges 29C being sewn together at the peripheral edgeportion of the upper chamber 28 (sewn portion S3).

Note that the sewing of the sewn portions S1, S3 can be carried out atone time by continuously sewing-together the peripheral edge portion ofthe side airbag 16, but are not limited to this, and may be carried outseparately. Further, in the illustrated example, the upper chamber 28 isformed by sewing the end edges 29C of the pair of upper base cloths 29,but is not limited to this, and the single upper base cloth 29 may be,for example, folded in two toward the seat rear side (vehicle rear side)with the seat front side as the center, and the end edges 29C may besewn together at the peripheral edge portion. Moreover, the upperchamber 28 is not limited to being formed by sewing the end edges 29C ofthe upper base cloths 29, and, for example, may be formed bybag-weaving.

As shown in FIG. 1, FIG. 2, the inflator 18 is a gas generating sourcefor supplying gas for inflation into the side airbag 16, and, forexample, is formed in the form of a tube, and is disposed, for example,at the seat rear end portion within the upper chamber 28 in a state inwhich gas jetting-out portions 18A are directed toward a lower chamber26 side (check valve 24 side).

A diffuser 34 that guides the flow of gas for inflation, that isjetted-out from the gas jetting-out portions 18A, mainly to the lowerchamber 26 side and also guides the flow of gas to the upper chamber 28side, is disposed within the upper chamber 28. The gas jetting-outportions 18A of the inflator 18 are disposed within the diffuser 34.This diffuser 34 is structured by forming a diffuser base cloth 35 inthe form of a tube so as to surround at least the gas jetting-outportions 18A from the entire periphery of the peripheral directionthereof, and has a lower opening portion 34D, that is an example of amain opening portion that opens to the vehicle lower side toward thelower chamber 26 side, and an upper opening portion 34U, that is anexample of an auxiliary opening portion that opens to the vehicle upperside toward the upper chamber 28 side.

This diffuser 34 is fixed to the upper base cloths 29 by, for example,the single diffuser base cloth 35 being folded in two or rounded in theform of a tube, and rear end edges 35R thereof being sewn together withthe end edges 29C of the upper base cloths 29 at the sewn portion S3.Further, within the upper chamber 28, the diffuser 34 is disposed so asto be adjacent to the check valve 24 for example. This is in order topreferentially supply, to the lower chamber 26 that is the high pressurechamber, the gas for inflation from the inflator 18 at the time of aside collision. Note that, in the illustrated example, the vehicle upperend portion of the inflator 18 is exposed from the diffuser 34, but thelength of the diffuser 34 is arbitrary, and the entire inflator 18 maybe structured so as to be contained within the diffuser 34.

Although not illustrated, for example, two stud bolts that extend towardthe seat transverse direction inner side are provided to stand at theinflator 18. Due to these stud bolts being passed through a seat backframe (not illustrated) within the seat back 14 and nuts (notillustrated) being fastened to these stud bolts, the inflator 18 isfixed to the seat back frame together with the side airbag 16. Further,the inflator 18 is connected to an airbag ECU via a wire harness, and isstructured to operate by operation current from the airbag ECU andsupply gas for inflation to the side airbag 16. The airbag ECU isstructured so as to cause operation current to flow to the inflator 18when the airbag ECU judges a side collision due to a signal from acollision sensor (not illustrated).

In FIG. 1 through FIG. 8, the partitioning wall 22 is formed by aportion of the lower base cloth 27 that forms the lower chamber 26, andis provided so as to divide the lower chamber 26 and the upper chamber28, and has a folded-in end edge 22A that is folded-in convexly towardthe lower chamber 26 side when the side airbag 16 is not inflated. InFIG. 3, the folded-in end edge 22A is the region that is first folded intwo when the lower base cloth 27 is folded and the lower chamber 26 isformed. A seat rear end portion 22B of this folded-in end edge 22A iscut so as to structure the check valve 24.

Further, as shown in FIG. 2 through FIG. 4, a sewn portion S4 that issemicircular for example is provided at the folded-in end edge 22A, atthe seat front side (vehicle front side) of the seat rear end portions22B, that is adjacent to a partial region, that becomes the check valve24, of the partitioning wall 22. This sewn portion S4 is formed in anarcuate shape for example. Due thereto, as shown in FIG. 2, a length Lsfrom the upper end portions 27U of the lower base cloth 27 (the borderportion between the base cloth of the side airbag 16 and thepartitioning wall 22) to the sewn portion S4 is set to be shorter than alength L from the upper end portions 27U of the lower base cloth 27,further toward the seat rear side than the sewn portion S4, to thefolded-in end edge 22A (the seat rear end portions 22B). Due thereto, arange L-Ls at the vehicle upper side from the folded-in end edge 22A canbe made to function as the check valve 24. In other words, the partialregion, of the partitioning wall 22, that is further toward the seatrear side than the sewn portion S4 can be made to function as the checkvalve 24.

Note that the shape of the sewn portion S4 is not limited to an arcuateshape, and it suffices for the relationship of the lengths Ls, L to beLs<L. Further, as shown in FIG. 2, in a case in which the partitioningwall 22 is set to a constant width, the length from the upper endportions 27U of the lower base cloth 27 at the seat front side of thesewn portion S4 to the folded-in end edge 22A also is L.

In FIG. 1, FIG. 2, FIG. 5, FIG. 9, FIG. 10, the check valve 24 isprovided at a partial region, e.g., the seat rear side, of thepartitioning wall 22, and is provided convexly toward the lower chamber26 side when the side airbag 16 is not inflated, and is structured so asto permit flowing of the gas for inflation from the upper chamber 28side to the lower chamber 26 side, and restrict flowing of gas in thedirection opposite thereto. This check valve 24 is formed integrallywith the partitioning wall 22 by cutting the seat rear end portions 22Bof the folded-in end edge 22A at the partitioning wall 22, and further,providing the sewn portion S4.

As shown in FIG. 9, when the inflator 18 operates, at the time when thegas that is jetted-out from the gas jetting-out portions 18A of theinflator 18 is jetted-out from the lower opening portion 34D of thediffuser 34 toward the lower chamber 26, due to the pressure thereof,the check valve 24 opens in the form of a tube for example. On the otherhand, as shown in FIG. 10, after the jetting-out of gas from theinflator 18 ends, even if gas attempts to flow backward from the lowerchamber 26 side that is the high pressure chamber to the upper chamber28 side that is the low pressure chamber, such backward flow of gas issuppressed due to the check valve 24 closing.

In addition, end edges 22E at the seat rear side of the partitioningwall 22, that become the rear ends of the check valve 24, are sewn tothe end edges 27C of the lower base cloth 27 at the sewn portion S1. Byfixing the rear end of the check valve 24 in this way, when gas attemptsto flow backward from the lower chamber 26 to the upper chamber 28,inverting of the check valve 24 toward the upper chamber 28 side can besuppressed even more.

(Operation)

The present embodiment is structured as described above, and theoperation thereof is described hereinafter. In FIG. 1, at the sideairbag device 10 relating to the present embodiment, the side airbag 16has the lower chamber 26 that becomes the high pressure side at the timeof inflation and expansion, and upper chamber 28 that becomes lowerpressure than the lower chamber 26, and the lower chamber 26 and theupper chamber 28 are divided by the partitioning wall 22. The lowerchamber 26 and the upper chamber 28 are formed by base cloths that arerespectively separate bodies (the lower base cloth 27, the upper basecloths 29), and the partitioning wall 22 is formed by a portion of thelower base cloth 27 that forms the lower chamber 26. Therefore, costsrequired for sewing the side airbag 16 can be reduced as compared with astructure in which the lower base cloth 27 and the partitioning wall 22are made to be separate bodies.

Further, the internal pressure of the lower chamber 26 is maintained bythe check valve 24, and this check valve 24 is provided at a partialregion of the partitioning wall 22. Therefore, as compared with astructure in which the check valve 24 is provided separately, costsrequired for sewing the side airbag 16 is reduced, and smaller size andlighter weight of the package formed by folding-up the side airbag 16can be devised.

Moreover, because the lower base cloth 27 that forms the lower chamber26 is folded in two convexly toward the lower chamber 26 side at theregion that becomes the central portion of the partitioning wall 22, itis easy to make a partial region of the partitioning wall 22 be thecheck valve 24. Further, sewing of the side airbag 16 can be lessenedbecause the lower base cloth 27 that forms the lower chamber 26 isfolded-over respectively toward the bag outer sides and the lowerchamber 26 side at both end portions in the bag thickness direction ofthe region that becomes the partitioning wall 22, and the end edges aresewn together at the peripheral edge portion of the lower chamber 26.Therefore, the mass-productivity of the side airbag 16 can be improved.

Operation of the side airbag device 10 at the time of a side collisionis described next. When the airbag ECU judges the occurrence of the sidecollision on the basis of a signal from an unillustrated collisionsensor, operation current is made to flow from the airbag ECU to theinflator 18. The inflator 18 receives the operation current andoperates, and jets a large amount of gas out from the gas jetting-outportions 18A.

As shown in FIG. 9, due to this gas for inflation being distributedthrough the diffuser 34 to the lower chamber 26 and the upper chamber 28of the side airbag 16, the side airbag 16 inflates from the side portionof the seat back 14, and inflates and expands between a vehicle sideportion (not illustrated) and the passenger 32.

Concretely, the gas that is supplied from the inflator 18 into thediffuser 34 is jetted-out through the lower opening portion 34D of thediffuser 34 to the lower chamber 26 side. Here, within the upper chamber28, the diffuser 34 is disposed adjacent to the check valve 24 forexample, and further, the folded-in end edge 22A of the partitioningwall 22 that forms the check valve 24 is folded-in from the upper endportions 27U of the lower base cloth 27 convexly toward the lowerchamber 26 side. Therefore, the check valve 24 can be opened easily bythe pressure of the gas that is jetted-out from the lower openingportion 34D of the diffuser 34. Due thereto, because flowing of gas fromthe upper chamber 28 side to the lower chamber 26 side at the checkvalve 24 is permitted, gas from the inflator 18 is supplied in the arrowA direction into the lower chamber 26 through the check valve 24.

Further, the gas that is jetted-out from the inflator 18 is guided alsoin the arrow B direction through the gap between the inflator 18 and thediffuser 34, and is supplied into the upper chamber 28 through the upperopening portion 34U of the diffuser 34 (see FIG. 2 as well). Because thegas jetting-out portions 18A of the inflator 18 are disposed so as to bedirected toward the lower chamber 26 side, the gas that is jetted-outfrom the gas jetting-out portions 18A is preferentially supplied to thelower chamber 26. Accordingly, the lower chamber 26 can be inflated andexpanded before the upper chamber 28.

Here, the folded-in end edge 22A of the partitioning wall 22 isfolded-in from the upper end portions 27U of the lower base cloth 27convexly toward the lower chamber 26 side. Accordingly, even if the seatrear end portions 22B (the check valve 24) of the folded-in end edge 22Aand the outer surface of the diffuser 34 are contacting, when the gas ofthe upper chamber 28 side attempts to flow to the lower chamber 26 side,a gap arises between the partitioning wall 22 and the diffuser 34.Therefore, flowing of gas from the upper chamber 28 side to the lowerchamber 26 side at the check valve 24 is permitted.

Here, FIG. 6 is an enlarged sectional view seen in the direction ofarrows F6-F6 in FIG. 2, showing an example of the state of thepartitioning wall 22 when the side airbag 16 is not inflated. Further,FIG. 7 is an enlarged sectional view seen in the direction of arrowsF7-F7 in FIG. 2, showing the state of the partitioning wall 22 when theside airbag is inflated and expanded. Accompanying the enlarging of thebag thickness when the side airbag 16 inflates and expands, from thestate of FIG. 6 to the state of FIG. 7, the partitioning wall 22 becomesa state of being spread-out in the vehicle transverse direction (thethickness direction of the side airbag 16). The one-side bag thicknessof the side airbag 16 at this cross-sectional position is Wf. Here, theone-side bag thickness means half of the bag thickness.

FIG. 8 is an enlarged sectional view seen in the direction of arrowsF8-F8 in FIG. 2, showing an example of the state the partitioning wall22 at the position of the sewn portion S4, when the side airbag 16 isinflated and expanded. As shown in FIG. 2, at the position of the sewnportion S4, the length Ls from the upper end portions 27U of the lowerbase cloth 27 to the sewn portion S4 is set to be shorter than thelength L from the upper end portions 27U of the lower base cloth 27,further toward the seat rear side than the sewn portion S4, to thefolded-in end edge 22A (the seat rear end portions 22B) (Ls<L).Accordingly, the width of the partitioning wall 22 when the side airbag16 inflates and expands becomes narrower than the width of thepartitioning wall 22 at the seat front side of the sewn portion S4. Theone-side bag width of the side airbag 16 at this cross-sectionalposition is Ws.

FIG. 9 is an enlarged sectional view seen in the direction of arrowsF9-F9 in FIG. 2, showing an example of the partitioning wall 22 (thecheck valve 24) at a time when gas, that is jetted-out from the gasjetting-out portions 18A of the inflator 18, flows into the lowerchamber 26. The sewn portion S4 that is semi-circular is provided at thefolded-in end edge 22A, at the seat front side of the seat rear endportions 22B, that is adjacent to the partial region, of thepartitioning wall 22, that becomes the check valve 24. Further, the endedges 22E at the seat rear side where the check valve 24 is positioned,of the partitioning wall 22, are sewn to the end edges 27C of the lowerbase cloth 27 at the sewn portion S1. Therefore, when the side airbag 16inflates and expands, the spreading-out of the partitioning wall 22 atthe position of the check valve 24 is limited. The one-side bagthickness of the side airbag 16 at this cross-sectional position is Wr.

FIG. 11 is an enlarged sectional schematic view of main portions seen inthe direction of arrows F11-F11 in FIG. 2, showing examples of inflatedthicknesses of respective portions of the side airbag 16. As shown inthis FIG. 11, the relationship between Wf, Ws, Wr is, for example,Wf>Wr>Ws. Note that the relationship between the inflated thicknesses ofthe respective portions is not limited to this, and, as shown in FIG.12, may be Wr≈Wf>Ws. Note that, as shown in FIG. 1, when the side airbag16 inflates and expands, the portion that is the sewn portion S4 ispositioned at the side portion of the seat back 14, and does notcontribute very much to the restraining of the passenger 32.Accordingly, by suppressing the inflated thickness of such a region, thebag volume of the side airbag 16 is cut-down, and the side airbag 16 canbe inflated and expanded more rapidly into the space between thepassenger 32 and the vehicle side portion (not illustrated).

Next, as shown in FIG. 10, when jetting-out of gas from the inflator 18ends, gas attempts to flow backward from the lower chamber 26 side thatis the high pressure chamber to the upper chamber 28 side that is thelow pressure chamber, but, due to the check valve 24 closing at thistime, such backward flow of gas is restricted.

Concretely, in FIG. 2, the sewn portion S4 is provided such that Ls<L.Therefore, of the seat rear end portions 22B of the folded-in end edge22A, the range of L-Ls at the vehicle upper side from the folded-in endedge 22A can be made to function as the check valve 24. Due thereto, asshown in FIG. 10, even in a state in which the partitioning wall 22 isspread-out in the vehicle transverse direction due to the inflation andexpansion of the side airbag 16, a region at which the seat rear endportions 22B of the folded-in end edge 22A fit snugly together can beensured. Further, of the partitioning wall 22, the end edges 22E at theseat rear side at which the check valve 24 is positioned are fixed bybeing sewn to the end edges 27C of the lower base cloth 27 at the sewnportion S1. Therefore, inverting of the check valve 24 toward the upperchamber 28 side can be suppressed even more.

In this way, when gas attempts to flow backward from the lower chamber26 to the upper chamber 28, because the check valve 24 is closed by theinternal pressure of the lower chamber 26, such backward flow of gas canbe restricted, and the internal pressure of the lower chamber 26 can bemaintained over a longer time. Accordingly, as shown in FIG. 1, thewaist portion 32W of the passenger 32 seated in the vehicle seat 12 canbe restrained at an early stage and in a high pressure state by thelower chamber 26. Further, because the internal pressure of the lowerchamber 26 can be maintained by the check valve 24 for a longer time,the passenger restraining performance at the time of a side collisioncan be improved more.

On the other hand, gas is preferentially supplied to the lower chamber26, and, due to the backward flow of gas from the lower chamber 26 sideto the upper chamber 28 being restricted, the upper chamber 28 is in arelatively low pressure state. As shown in FIG. 1, the chest portion32C, the shoulder portion 32S, the upper arm portion (not illustrated),and the abdomen portion 32A of the passenger 32 can be restrained at anappropriate restraining force by the upper chamber 28.

Further, due to the lower chamber 26 and the upper chamber 28 at theside airbag 16 being divided by the partitioning wall 22 that has apredetermined width, as compared with a structure in which a bag portionfor the chest portion and a bag portion for the waist portion aredivided due to sewing together at the border portion thereof, the bagthickness of the side airbag 16 at the border portion can be ensured tobe large, and the inflation and expansion of the side airbag 16 can bestabilized more.

(Method of Sewing Side Airbag)

The method of sewing the side airbag 16 relating to the presentembodiment is a method of sewing a side airbag that has the lowerchamber 26 that becomes the high pressure side at the time of inflationand expansion, and the upper chamber 28 that becomes lower pressure thanthe lower chamber 26, and in which the lower chamber 26 and the upperchamber 28 are formed by base cloths (the lower base cloth 27, the upperbase cloths 29) that are respectively separate bodies and are divided bythe partitioning wall 22, and the partitioning wall 22 is formed by aportion of the lower base cloth 27 that forms the lower chamber 26, themethod having a step of forming, at a partial region of the partitioningwall 22, the check valve 24 that permits flowing of gas for inflationfrom the upper chamber 28 side to the lower chamber 26 side, andrestricts flowing of gas in the direction opposite thereto.

Further, the method of sewing the side airbag 16 relating to the presentembodiment has a step of folding the lower base cloth 27, that forms thelower chamber 26, in two convexly toward the lower chamber 26 side atthe region that becomes the central portion of the partitioning wall 22,and sewing both end portions in the bag thickness direction (the upperend portions 27U of the lower base cloth 27) of the region that becomesthe partitioning wall 22 to the upper base cloths 29 that form the upperchamber 28, and a step of folding-over the lower base cloth 27 thatforms the lower chamber 26, respectively toward the bag outer sides andthe lower chamber 26 side at both end portions in the bag thicknessdirection (the upper end portions 27U of the lower base cloth 27) of theregion that becomes the partitioning wall 22, and, at the peripheraledge portion of the lower chamber 26, sewing together the end edges 27Cof the lower base cloth 27 that forms the lower chamber 26, and, at theperipheral edge portion of the upper chamber 28, sewing together the endedges 29C of the upper base cloths 29 that form the upper chamber 28.

In accordance with this method of sewing, the partitioning wall 22 isformed by a portion of the lower base cloth 27 that forms the lowerchamber 26. Therefore, as compared with a structure in which the lowerbase cloth 27 and the partitioning wall 22 are made to be separatebodies, costs required for sewing the side airbag 16 can be reduced.

Further, the check valve 24 for maintaining the internal pressure of thelower chamber 26 is formed by a partial region of the partitioning wall22 being cut and being folded-in convexly toward the lower chamber 26side. Therefore, as compared with a structure in which the check valve24 is provided separately, costs required for sewing the side airbag 16is reduced, and smaller size and lighter weight of the package formed byfolding-up the side airbag 16 can be devised.

Moreover, by sewing together the end edges of the respective base cloths(the respective end edges 27C of the lower base cloth 27, the respectiveend edges 29C of the upper base cloths 29) at the peripheral edgeportion of the lower chamber 26 and the peripheral edge portion of theupper chamber 28, the lower chamber 26 and the upper chamber 28 can beformed by sewing of a single time.

Second Embodiment

In FIG. 13, FIG. 14, at a side airbag device 20 relating to the presentembodiment, the method of sewing the lower chamber 26 that is the highpressure chamber differs from the first embodiment. Concretely, thelower base cloth 27 that forms the lower chamber 26 is folded in two ata bottom portion 26A of the lower chamber 26, and is folded-overrespectively toward the bag inner side and the lower chamber 26 side atboth end portions in the bag thickness direction (the upper end portions27U of the lower base cloth 27) of the region that becomes thepartitioning wall 22, and end edges 27D are sewn together (sewn portionsS5, S6) at the region that becomes the central portion of thepartitioning wall 22, and the end edges 27C that are positioned at theperipheral edge portion of the lower chamber 26 are sewn together (sewnportion S1).

As shown in FIG. 13, the length from the upper end portions 27U to theend edges 27D at the lower base cloth 27 increases rectilinearly fromthe seat front side toward the seat rear side for example, and becomes amaximum (length L) at seat rear end portions 27B of the end edges 27Dthat become the check valve 24. On the other hand, the length Ls fromthe upper end portions 27U to the sewn portion S5 is shorter than thelength L, and is constant for example, and the ridge lines of the upperend portions 27U and the sewn portion S5 are substantially parallel. Thesewn portion S6 extends in a direction intersecting the sewn portion S5,from the seat rear end portion of the sewn portion S5 to the end edges27D. The sewn portions S5, S6 can be sewn at one time by rotating thelower base cloth 27 at the intersection point of the sewn portions S5,S6.

By providing the sewn portion S6 in this way, the range of L−Ls at thevehicle upper side from the end edges 27D, of the seat rear end portions27B of the end edges 27D, can be made to function as the check valve 24.In other words, a partial region, that is further toward the seat rearside than the sewn portion S6, at the partitioning wall 22 can be madeto function as the check valve 24.

Because the other portions are similar to the first embodiment, the sameportions are denoted by the same reference numerals in the drawings, anddescription thereof is omitted.

(Operation)

The present embodiment is structured as described above, and theoperation thereof is described hereafter. In FIG. 13, at the side airbagdevice 20 relating to the present embodiment, the lower base cloth 27that forms the lower chamber 26 is folded in two at the bottom portion26A of the lower chamber 26, and, at both end portions in the bagthickness direction (the upper end portions 27U) of the region thatbecomes the partitioning wall 22, is folded-over respectively toward thebag inner side and the lower chamber 26 side, and, at the region thatbecomes the central portion of the partitioning wall 22, the end edges27D are sewn together. Therefore, it is easy to make a partial region ofthe partitioning wall 22 be the check valve 24. Further, sewing of theside airbag 16 can be lessened because the lower chamber 26 is formed bythe end edges 27C of the lower base cloth 27, that are positioned at theperipheral edge portion of the lower chamber 26, being sewn together atthe lower base cloth 27 that forms the lower chamber 26. Therefore, themass-productivity of the side airbag 16 can be improved.

At the time of a side collision, when the inflator 18 operates and theside airbag 16 inflates and expands, as shown in FIG. 17, the checkvalve 24 opens due to pressure of the gas that is jetted-out from thelower opening portion 34D of the diffuser 34, and gas from the inflator18 is supplied in the arrow A direction into the lower chamber 26through the check valve 24. Further, at this time, gas that isjetted-out from the inflator 18 is guided also in the arrow B directionthrough the gap between the inflator 18 and the diffuser 34, and issupplied into the upper chamber 28 through the upper opening portion 34Uof the diffuser 34 (see FIG. 13 as well).

Because the gas jetting-out portions 18A of the inflator 18 are disposedso as to be directed toward the lower chamber 26 side, gas that isjetted-out from the gas jetting-out portions 18A is preferentiallysupplied to the lower chamber 26. Accordingly, the lower chamber 26 canbe inflated and expanded before the upper chamber 28.

Here, FIG. 15 is an enlarged sectional view seen in the direction ofarrows F15-F15 in FIG. 13, showing an example of the state of thepartitioning wall 22. As shown in FIG. 13, accompanying the enlarging ofthe bag thickness at the time of inflation and expansion of the sideairbag 16, the partitioning wall 22 becomes a state of being spread-outin the vehicle transverse direction (the thickness direction of the sideairbag 16).

FIG. 16 is an enlarged sectional schematic view of main portions seen inthe direction of arrows F16-F16 in FIG. 13, showing an example of thestate of the partitioning wall 22 in the vicinity of the check valve 24when the side airbag 16 is inflated and expanded. As shown in FIG. 13,at the position of the sewn portion S6, the length Ls from the upper endportions 27U of the lower base cloth 27 to the sewn portion S5 is set tobe shorter than the length L from the upper end portions 27U furthertoward the seat rear side than the sewn portion S4, to the end edges 27D(the seat rear end portions 27B) of the lower base cloth 27 (Ls<L).Accordingly, as shown in FIG. 15, FIG. 16, the width of the partitioningwall 22 at the position of the sewn portion S6 when the side airbag 16is inflated and expanded, is narrower than the width of the partitioningwall 22 at the seat front side of the sewn portion S5.

Next, as shown in FIG. 18, when the jetting-out of gas from the inflator18 ends, gas attempts to flow backward from the lower chamber 26 sidethat is the high pressure chamber to the upper chamber 28 side that isthe low pressure chamber, but such backward flow of the gas isrestricted due to the check valve 24 closing at this time.

Concretely, in FIG. 13, the sewn portion S6 is provided such that Ls<L.Therefore, of the seat rear end portions 27B of the end edges 27D, therange of L-Ls at the vehicle upper side from the end edges 27D can bemade to function as the check valve 24. Due thereto, as shown in FIG.18, even in the state in which the partitioning wall 22 has spread-outin the vehicle transverse direction due to the inflation and expansionof the side airbag 16, a region at which the seat rear end portions 27Bof the end edges 27D fit snugly together can be ensured.

(Method of Sewing Side Airbag)

The method of sewing the side airbag 16 relating to the presentembodiment is a method of sewing a side airbag that has the lowerchamber 26 that becomes the high pressure side, and the upper chamber 28that becomes lower pressure than the lower chamber 26 at the time ofinflation and expansion, and in which the lower chamber 26 and the upperchamber 28 are formed by base cloths (the lower base cloth 27, the upperbase cloths 29) that are respectively separate bodies and are divided bythe partitioning wall 22, and the partitioning wall 22 is formed by aportion of the lower base cloth 27 that forms the lower chamber 26, themethod having a step of forming, at a partial region of the partitioningwall 22, the check valve 24 that permits flowing of gas for inflationfrom the upper chamber 28 side to the lower chamber 26 side, andrestricts flowing of gas in the direction opposite thereto.

Further, the method of sewing the side airbag 16 relating to the presentembodiment has a step of folding the lower base cloth 27, that forms thelower chamber 26 that is the high pressure chamber, in two at the bottomportion 26A of the lower chamber 26, and sewing both end portions in thebag thickness direction (the upper end portions 27U of the lower basecloth 27) of the region that becomes the partitioning wall 22, of thelower base cloth 27, to the upper base cloths 29 that form the upperchamber 28 that is the low pressure chamber, and a step of folding-overthe lower base cloth 27 that forms the lower chamber 26, respectivelytoward the bag inner side and the lower chamber 26 side from theposition sewn with the upper base cloths 29 that form the upper chamber28, and sewing the end edges 27D thereof together excluding the partialregion that becomes the check valve 24, and a step of, at the peripheraledge portion of the lower chamber 26, sewing together the end edges 27Cof the lower base cloth 27 that forms the lower chamber 26, and, at theperipheral edge portion of the upper chamber 28, sewing together the endedges 29C of the upper base cloths 29 that form the upper chamber 28.

In accordance with this method of sewing, the partitioning wall 22 isformed by a portion of the lower base cloth 27 that forms the lowerchamber 26. Therefore, as compared with a structure in which the lowerbase cloth 27 and the partitioning wall 22 are made to be separatebodies, costs required for sewing the side airbag 16 can be reduced.

Further, the check valve 24 for maintaining the internal pressure of thelower chamber 26 is formed by the end edges 27D of the lower base cloth27 being sewn together, excluding the partial region that becomes thecheck valve 24. Therefore, as compared with a structure in which thecheck valve 24 is provided separately, costs required for sewing theside airbag 16 is reduced, and smaller size and lighter weight of thepackage formed by folding-up the side airbag 16 can be devised.

Moreover, at the peripheral edge portion of the lower chamber 26, theend edges 27C of the lower base cloth 27 that forms the lower chamber 26are sewn together, and, at the peripheral edge portion of the upperchamber 28, the end edges 29C of the upper base cloths 29 that form theupper chamber 28 are sewn together, and the lower chamber 26 and theupper chamber 28 can thereby be formed by sewing of a single time.Therefore, costs required for sewing the side airbag 16 can be furtherreduced.

Third Embodiment

From FIG. 19 to FIG. 21, a side airbag device 30 relating to the presentembodiment has, as high pressure chambers of the side airbag 16, thelower chamber 26 that corresponds to the waist portion 32W of thepassenger 32 seated in the vehicle seat 12 and an upper chamber 38 thatcorresponds to the shoulder portion 32S of the passenger 32, and, as alow pressure chamber of the side airbag 16, an intermediate chamber 36that is positioned between the upper chamber 38 and the lower chamber 26and that corresponds to the chest portion 32C of the passenger 32. Thelower chamber 26 and the intermediate chamber 36 are divided by a lowerpartitioning wall 42, and the lower partitioning wall 42 is a regioncorresponding to the partitioning wall 22 of the second embodiment.Further, the upper chamber 38 and the intermediate chamber 36 aredivided by an upper partitioning wall 52. The structure and the methodof sewing the lower chamber 26 are similar to the structure of the firstembodiment or the second embodiment. The illustrated structure is thestructure of the second embodiment. Although not illustrated, the bagthickness of the lower chamber 26 is set to be thicker than the bagthickness of the upper chamber 38.

Further, the upper chamber 38 is structured similarly to the lowerchamber 26, and is disposed with the upper side and the lower sidethereof being the reverse of those of the lower chamber 26. Concretely,an upper base cloth 39 that forms the upper chamber 38 is folded in twoat a bottom portion 38A of the upper chamber 38, and, at both endportions in the bag thickness direction (lower end portions 39D of theupper base cloth 39) of the region that becomes the upper partitioningwall 52, is folded-over respectively toward the bag inner side and theupper chamber 38 side, and, at the region that becomes the centralportion of the upper partitioning wall 52, end edges 39U are sewntogether (sewn portions S7, S8), and end edges 39C that are positionedat the peripheral edge portion of the upper chamber 38 are sewn together(sewn portion S9).

The length from the lower end portions 39D to the end edges 39U at theupper base cloth 39 increases rectilinearly from the seat front sidetoward the seat rear side for example, and becomes a maximum at the seatrear end portions 39B of the end edges 39U that become an upper checkvalve 54. On the other hand, the length from the lower end portions 39Dto the sewn portion S7 is constant for example, and the ridge lines ofthe lower end portions 39D and the sewn portion S7 are substantiallyparallel. The sewn portion S8 extends in a direction intersecting thesewn portion S7, from the seat rear end portion of the sewn portion S7to the end edges 39U. The sewn portions S8, S9 can be sewn at one timeby rotating the upper base cloth 39 at the intersection point of thesewn portions S8, S9.

Of the lower partitioning wall 42, end edges 42E at the seat rear sidewhere a lower check valve 44 is positioned are sewn to the end edges 27Cof the lower base cloth 27 at the sewn portion S1. Further, of the upperpartitioning wall 52, end edges 52E at the seat rear side where theupper check valve 54 is positioned are sewn to the end edges 39C of theupper base cloth 39 at the sewn portion S9.

The intermediate chamber 36 is formed by sewing lower end portions 37Dof a pair of central base cloths 37 for example, that are positioned atthe bag thickness direction both sides, to the upper end portions 27U ofthe lower base cloth 27 that forms the lower chamber 26 (sewn portionsS2), and sewing upper end portions 37U to the lower end portions 39D ofthe upper base cloth 39 that forms the upper chamber 38 (sewn portionsS10), and further, sewing end edges 37C together at the peripheral edgeportion of the intermediate chamber 36 (sewn portion S11).

Note that the sewing at the sewn portions S1, S11, S9 can be carried outat one time by continuously sewing the peripheral edge portion of theside airbag 16, but are not limited to this, and may be carried outseparately. Further, in the illustrated example, the intermediatechamber 36 is formed by sewing the end edges 37C of the pair of centralbase cloths 37, but is not limited to this, and the single central basecloth 37 may be folded in two toward the seat rear side (vehicle rearside) with the seat front side as the center for example, and the endedges 37C may be sewn together at the peripheral edge portion. Moreover,the intermediate chamber 36 is not limited to being formed by the endedges 37C of the central base cloths 37 being sewn, and, for example,may be formed by bag-weaving.

The diffuser 34 is structured to guide the gas for inflation mainly tothe lower chamber 26 side and the upper chamber 38 side, and to guidethe gas also to the intermediate chamber 36 side, and has the loweropening portion 34D that is an example of a main opening portion thatopens to the lower chamber 26 side, and the upper opening portion 34Uthat is an example of a main opening portion that opens respectively tothe upper chamber 38 side, and front opening portions 34F that areexamples of auxiliary opening portions that open to the intermediatechamber 36 side.

This diffuser 34 is fixed to the central base cloths 37 by, for example,the single diffuser base cloth 35 being folded in two or rounded in theform of a tube, and the rear end edges 35R thereof being sewn togetherwith the end edges 37C of the central base cloths 37 at the sewn portionS11. The lower opening portion 34D is disposed adjacent to the lowercheck valve 44 that is provided at the lower partitioning wall 42, andthe upper opening portion 34U is disposed adjacent to the upper checkvalve 54 that is provided at the upper partitioning wall 52.

Note that, in the same way as the first embodiment, the inflator 18 mayhave the gas jetting-out portions 18A only at the lower chamber 26 sidethat corresponds to the waist portion 32W of the passenger 32. This isbecause, when the passenger 32 is restrained by the side airbag 16, itis preferable to restrain the waist portion 32W at an earlier stage thanthe shoulder portion 32S.

As shown in FIG. 21, the front opening portions 34F of the diffuser 34are plural through-holes whose opening surface area is small as comparedwith the lower opening portion 34D and the upper opening portion 34U forexample.

The inflator 18 that is disposed within the diffuser 34 has the gasjetting-out portions 18A at both ends for example, and can supply gasfor inflation preferentially to the lower chamber 26 and the upperchamber 38.

Because the other portions are similar to the first embodiment or thesecond embodiment, the same portions are denoted by the same referencenumerals in the drawings, and description thereof is omitted.

(Operation)

The present embodiment is structured as described above, and theoperation thereof is described hereafter. In FIG. 19, at the side airbagdevice 30 relating to the present embodiment, at the side airbag 16 inthe inflated and expanded state, the high pressure chambers are thelower chamber 26 that corresponds to the waist portion 32W of thepassenger 32 seated in the vehicle seat 12 and the upper chamber 38 thatcorresponds to the shoulder portion 32S of the passenger 32, and the lowpressure chamber is the intermediate chamber 36 that is positionedbetween the upper chamber 38 and the lower chamber 26 and thatcorresponds to the chest portion 32C of the passenger 32. Therefore,when the side airbag 16 inflates and expands, the lower chamber 26 andthe upper chamber 38 become higher pressure than the intermediatechamber 36.

Concretely, the gas, that is jetted-out from the gas jetting-outportions 18A at the upper and lower ends when the inflator 18 operates,is supplied mainly to the lower chamber 26 and the upper chamber 38through the diffuser 34, and further, is also supplied to theintermediate chamber 36. To describe in more detail, the gas that issupplied into the diffuser 34 from the inflator 18 is jetted-out to thelower chamber 26 side through the lower opening portion 34D of thediffuser 34, and is jetted-out to the upper chamber 38 side through theupper opening portion 34U.

The lower check valve 44 opens due to the pressure of the gas jetted-outfrom the lower opening portion 34D of the diffuser 34, and the uppercheck valve 54 opens due to the pressure of the gas jetted-out from theupper opening portion 34U of the diffuser 34. Due thereto, flowing ofgas to the lower chamber 26 and the upper chamber 38 is permitted, andtherefore, the gas from the inflator 18 is supplied into the lowerchamber 26 through the lower check valve 44, and is supplied into theupper chamber 38 through the upper check valve 54. Gas is suppliedthrough the front opening portions 34F of the diffuser 34 to theintermediate chamber 36.

Even when the jetting-out of gas from the inflator 18 ends and gasattempts to flow backward from the lower chamber 26 side and the upperchamber 38 side that are the high pressure chambers, the lower checkvalve 44 and the upper check valve 54 respectively close, and therefore,such backward flow of the gas is restricted. Therefore, the internalpressures of the lower chamber 26 and the upper chamber 38 can bemaintained over a longer time.

Further, the waist portion 32W of the passenger 32 seated in the vehicleseat 12 can be restrained by the lower chamber 26 that is relativelyhigh pressure, and the shoulder portion 32S of the passenger 32 can berestrained by the upper chamber 38 that similarly is relatively highpressure. Further, because the bag thickness of the lower chamber 26,that corresponds to the waist portion 32W of the passenger 32, is set tobe thicker than the bag thickness of the upper chamber 38 thatcorresponds to the shoulder portion 32S of the passenger 32, when thepassenger 32 is restrained by the side airbag 16, the restraining forcewith respect to the waist portion 32W can be generated at a timing thatis earlier than the shoulder portion 32S. Moreover, the chest portion32C of the passenger 32 can be restrained by the intermediate chamber 36that is relatively low pressure. In the present embodiment, theintermediate chamber 26 corresponds not only to the chest portion 32C ofthe passenger 32, but also to the abdomen portion 32A.

In this way, in accordance with the side airbag device 30, therespective portions of the upper body of the passenger 32 canrespectively be restrained at appropriate timings and by appropriaterestraining forces by the side airbag 16 that inflates and expandsbetween a vehicle side portion (not illustrated) and the passenger 32 atthe time of a side collision.

Fourth Embodiment

In FIG. 22 to FIG. 24, in a side airbag device 40 relating to thepresent embodiment, the diffuser 34 is extended up and down, and thelower opening portion 34D that is a main opening portion of the diffuser34 is disposed so as to pass through the lower check valve 44 at thelower chamber 26 side, and the upper opening portion 34U that is a mainopening portion of the diffuser 34 is disposed so as to pass through theupper check valve 54 at the upper chamber 38 side.

The rear end edges 35R of the diffuser base cloth 35, that arepositioned at the lower opening portion 34D of the diffuser 34, are sewntogether with the end edges 27C of the lower base cloth 27 at the sewnportion S1. Further, the rear end edges 35R of the diffuser base cloth35, that are positioned at the upper opening portion 34U of the diffuser34, are sewn together with the end edges 39C of the upper base cloth 39at the sewn portion S9. Due thereto, the positions of the lower openingportion 34D and the upper opening portion 34U of the diffuser 34 can bemade to be more stable.

Note that the main opening portions of the diffuser 34 may be structuredso as to pass through at least one of the lower check valve 44 of thelower chamber 26 side and the upper check valve 54 of the upper chamber38 side. Namely, there may be a structure in which the lower openingportion 34D that is a main opening portion passes through the lowercheck valve 44 of the lower chamber 26 side, and the upper openingportion 34U does not pass through the upper check valve 54 of the upperchamber 38 side. Or, there may be a structure in which the lower openingportion 34D does not pass through the lower check valve 44 of the lowerchamber 26 side, and the upper opening portion 34U passes through theupper check valve 54 of the upper chamber 38 side. In this way, bysetting the positions of the main opening portions of the diffuser 34,control of the distribution of the gas can be carried out easily.

Because the other portions are similar to the third embodiment, the sameportions are denoted by the same reference numerals in the drawings, anddescription thereof is omitted.

(Operation)

The present embodiment is structured as described above, and theoperation thereof is described hereafter. In FIG. 22 to FIG. 24, at theside airbag device 40 relating to the present embodiment, the diffuser34 is extended up and down, and the lower opening portion 34D that is amain opening portion of the diffuser 34 is disposed so as to passthrough the lower check valve 44 of the lower chamber 26 side, andfurther, the upper opening portion 34U that is a main opening portion ofthe diffuser 34 is disposed so as to pass through the upper check valve54 of the upper chamber 38 side. Therefore, the gas for inflation thatis supplied from the inflator 18 can be more directly guided to both thelower chamber 26 and the upper chamber 38. Concretely, the gas forinflation is guided in the arrow A direction toward the lower chamber 26side, and is guided in the arrow B direction toward the upper chamber 38side. In this way, by directly guiding the gas to the lower chamber 26and the upper chamber 38, both the lower chamber 26 and the upperchamber 38 can be inflated and expanded more rapidly and stably. Notethat, in FIG. 22, gas is supplied through the front opening portions 34Fof the diffuser 34 to the intermediate chamber 36.

As shown in FIG. 24, after inflation of the lower chamber 26 that is ahigh pressure chamber is completed, even if gas attempts to flowbackward from the lower opening portion 34D into the diffuser 34, thelower opening portion 34D closes due to the internal pressure of thelower chamber 26, and therefore, such backward flow of gas isrestricted. Similarly, after inflation of the upper chamber 38 that is ahigh pressure chamber is completed, even if gas attempts to flowbackward from the upper opening portion 34U into the diffuser 34, theupper opening portion 34U closes due to the internal pressure of theupper chamber 38, and therefore, such backward flow of gas isrestricted. Namely, the lower opening portion 34D and the upper openingportion 34U respectively have the function of a check valve.

Moreover, even if gas attempts to flow-in from the lower chamber 26 sideto the intermediate chamber 36 side through the gap between the diffuser34 and the lower partitioning wall 42, the lower partitioning wall 42(the lower check valve 44) fits snugly to the diffuser 34 due to theinternal pressure of the lower chamber 26, and therefore, such inflow ofgas is restricted. Similarly, even if gas attempts to flow-in from theupper chamber 38 side to the intermediate chamber 36 side through thegap between the diffuser 34 and the upper partitioning wall 52, theupper partitioning wall 52 (the upper check valve 54) fits snugly to thediffuser 34 due to the internal pressure of the upper chamber 38, andtherefore, such inflow of gas is restricted.

Accordingly, after the inflation and expansion of the side airbag 16,the internal pressures of the lower chamber 26 and the upper chamber 38can be maintained over a longer time.

Fifth Embodiment

In FIG. 25 through FIG. 28, in a side airbag device 50 relating to thepresent embodiment, end portions 37E, that run along the lengthdirection of the diffuser 34, at the central base cloths 37 that formthe intermediate chamber 36 are sewn to the side portions of thediffuser 34 (sewn portions S12) such that an overlapping region 56 ofthe central base cloths 37 and the diffuser 34 is reduced.

The structure and the method of sewing the lower chamber 26 and theupper chamber 38 are generally similar to the first embodiment. Thelower partitioning wall 42 has a folded-in end edge 42A that isfolded-in convexly toward the lower chamber 26 side when the side airbag16 is not inflated and expanded. This folded-in end edge 42A is theregion that is first folded in two when the lower base cloth 27 isfolded and the lower chamber 26 is formed.

A seat rear end portion 42B of this folded-in end edge 42A is cut inorder to form the lower check valve 44, and the diffuser 34 is passedthrough the lower check valve 44. Namely, the lower opening portion 34Dof the diffuser 34 is disposed within the lower chamber 26 that passesthrough the lower check valve 44. A front edge 35F of the diffuser basecloth 35 is partially sewn (sewn portion S13) to the folded-in end edge42A at a position intersecting the folded-in end edge 42A of the lowerpartitioning wall 42.

The length from the upper end portions 27U of the lower base cloth 27 tothe sewn portion S13 is set to be shorter than the length from the upperend portions 27U of the lower base cloth 27 further toward the seat rearside than the sewn portion S13, to the folded-in end edge 42A (the seatrear end portions 42B). Due thereto, the seat rear end portions 42B ofthe folded-in end edge 42A can be made to function as the lower checkvalve 44.

On the other hand, the upper partitioning wall 52 has a folded-in endedge 52A that is folded-in convexly toward the upper chamber 38 sidewhen the side airbag 16 is not inflated and expanded. This folded-in endedge 52A is the region that is first folded in two when the upper basecloth 39 is folded and the upper chamber 38 is formed.

A seat rear end portion 52B of this folded-in end edge 52A is cut inorder to form the upper check valve 54, and the diffuser 34 is passedthrough the upper check valve 54. Namely, the upper opening portion 34Uof the diffuser 34 passes through the upper check valve 54, and isdisposed within the upper chamber 38. The front edge 35F of the diffuserbase cloth 35 is partially sewn (sewn portion S14) to the folded-in endedge 52A at a position intersecting the folded-in end edge 52A of theupper partitioning wall 52.

The length from the lower end portions 39D of the upper base cloth 39 tothe sewn portion S14 is set to be shorter than the length from the lowerend portions 39D of the upper base cloth 39 further toward the seat rearside than the sewn portion S14, to the folded-in end edge 52A (the seatrear end portions 52B). Due thereto, the seat rear end portions 52B ofthe folded-in end edge 52A can be made to function as the upper checkvalve 54.

Note that the diffuser 34 is formed by, for example, the single diffuserbase cloth 35 being folded in two or rounded in the form of a tube, andthe rear end edges 35R thereof being sewn together (sewn portion S15).At the region overlapping the lower base cloth 27, these rear end edges35R are sewn together with the end edges 27C thereof (sewn portion S1),and further, at the region overlapping the upper base cloth 39, are sewntogether with the end edges 39C thereof (sewn portion S9).

The lower end portions 37D of the central base cloths 37 and the upperend portions 27U of the lower base cloth 27 are sewn at the sewnportions S2. At the region further toward the seat rear side than theend edges 37E of the central base cloths 37, these sewn portions S2 sewthe upper end portions 27U of the lower base cloth 27 and to thediffuser base cloth 35. Further, the upper end portions 37U of thecentral base cloths 37 and the lower end portions 39D of the upper basecloth 39 are sewn at the sewn portions S10. At the region further towardthe seat rear side than the end edges 37E of the central base cloths 37,these sewn portions S10 sew the lower end portions 39D of the upper basecloth 39 and the diffuser base cloth 35. Further, the end edges 37C atthe seat front side of the central base cloths 37 are sewn together atthe sewn portion S11. The intermediate chamber 36 is formed by carryingout such sewing.

The sewing at the sewn portions S1, S11, S9, S15 can be carried out atone time by continuously sewing-together the peripheral edge portion ofthe side airbag 16, but are not limited to this, and may be carried outseparately. Further, in the illustrated example, the intermediatechamber 36 is formed by sewing the pair of central base cloths 37, butis not limited to this, and the single central base cloth 37 may be, forexample, folded in two toward the seat rear side (vehicle rear side)with the seat front side as the center, and the end edges 37E may besewn to the side portions of the diffuser base cloth 35, and the upperend portions 37U may be sewn to the lower end portions 39D of the upperbase cloth 39, and the lower end portions 37D may be sewn to the upperend portions 27U of the lower base cloth 27.

In FIG. 25 through FIG. 28, in the side airbag device 50 relating to thepresent embodiment, the end portions 37E, that run along the lengthdirection of the diffuser 34, at the central base cloths 37 that formthe intermediate chamber 36 are sewn to the side portions of thediffuser 34 such that the overlapping region 56 of the central basecloths 37 and the diffuser 34 is reduced. In other words, the seatfront-back direction length of the central base cloths 37 is set to beshort so as to not cover as far as the rear end edges 35R of thediffuser base cloth 35, and the diffuser 34 is exposed. Further, thediffuser 34 also functions as one of inflated portions when the sideairbag 16 inflates and expands.

Accordingly, at the side airbag 50, the surface area of the central basecloths 37 that form the intermediate chamber 36 can be made to be small.Therefore, the materials cost of the side airbag 16 is reduced, and evensmaller size and lighter weight of the package formed by folding-up theside airbag 16 can be devised.

Note that, because the structures of the other portions of the sideairbag device 50 are similar to the fourth embodiment, the same portionsare denoted by the same reference numerals in the drawings, anddescription thereof is omitted. Further, because the operation when theside airbag 16 inflates and expands also is similar to the fourthembodiment, description thereof is omitted.

Sixth Embodiment

In FIG. 29, FIG. 30, a side airbag device 60 relating to the presentembodiment relates to, for example, a side airbag device that isinstalled at the side portion of the seat back 14 of the vehicle seat12, and has the side airbag 16, the inflator 18, a lower partitioningwall 62, a lower check valve 64, an upper partitioning wall 72, an uppercheck valve 74, and an intermediate partitioning wall 66.

The side airbag 16 is formed by sewing (sewn portion S16) peripheraledge portions 58C of a base cloth 58 that faces in the bag thicknessdirection, and is structured to, at the time of a side collision,swell-out from the side portion of the seat back 14 and inflate andexpand between a vehicle side portion (not illustrated) and thepassenger 32. The base cloth 58 is folded in two toward the seat frontside with an end edge 58E at the seat rear side being the center forexample, and the peripheral edge portions 58C are sewn at the sewnportion S16.

Further, the side airbag 16 has an initially inflated portion 68 towhich gas for inflation is supplied at the initial stage of inflationand expansion, a lower chamber 76 that becomes a high pressure side atthe time of inflation and expansion and corresponds to the waist portion32W of the passenger 32 seated in the vehicle seat 12, an upper chamber78 that becomes a high pressure side at the time of inflation andexpansion and corresponds to the shoulder portion 328 of the passenger32, and an intermediate chamber 80 that becomes lower pressure than thelower chamber 76 and the upper chamber 78 at the time of inflation andexpansion and corresponds to the chest portion 32C of the passenger 32.

The inflator 18 is a gas generating source for supplying gas forinflation into the initially inflated portion 68 of the side airbag 16,and is formed in the form of a tube for example, and is disposed, forexample, at the seat rear end portion within the initially inflatedportion 68 in a state in which the gas jetting-out portions 18A aredirected toward the lower chamber 76 side.

The upper partitioning wall 72 is provided within the side airbag 16,and divides the upper chamber 78 and the intermediate chamber 80, anddivides the upper chamber 78 and the initially inflated portion 68. Asshown in FIG. 31, this upper partitioning wall 72 is provided within theside airbag 16 by end edges 72A at bag thickness direction both sidesrespectively being sewn to the base cloth 58 that faces in the bagthickness direction (sewn portions S17).

The upper check valve 74 is provided at a partial region of the upperpartitioning wall 72, and is provided convexly toward the upper chamber78 side when the side airbag 16 is not inflated and expanded, and isstructured so as to permit flowing of gas for inflation from theinitially inflated portion 68 side to the upper chamber 78 side andrestrict gas flowing in the direction opposite thereto.

Concretely, as shown in FIG. 32, FIG. 34, the upper check valve 74 isformed by a rear end portion 72R of the upper partitioning wall 72 and arear side inner surface 16R of the side airbag 16, and is structuredsuch that the flow path of gas opens due to the rear end portion 72R ofthe upper partitioning wall 72 moving apart from the rear side innersurface 16R, and the gas flow path closes due to the rear end portion72R abutting the rear side inner surface 16R. In the illustratedexample, the position of the sewn portion S16 seen from the bag innerside is the rear side inner surface 16R of the side airbag 16.

At the upper partitioning wall 72, the slack of the rear end portion 72Ris set to be greater than a general portion 72B. Accordingly, due to thepressure of the gas that is supplied from the inflator 18 to theinitially inflated portion 68, the rear end portion 72R becomes convextoward the upper chamber 78 side, and the rear end portion 72R of theupper partitioning wall 72 moves away from the rear side inner surface16R of the side airbag 16. Due thereto, due to the upper check valve 74opening, flowing of gas in the arrow B direction from the initiallyinflated portion 68 side to the upper chamber 78 side is permitted.

On the other hand, as shown in FIG. 33, FIG. 35, when the jetting-out ofgas from the inflator 18 ends and gas attempts to flow backward from theupper chamber 78 side to the initially inflated portion 68 side, theupper check valve 74 attempts to invert toward the initially inflatedportion 68 side. Due to the rear end portion 72R of the upperpartitioning wall 72 fitting snugly to the rear side inner surface 16Rof the side airbag 16 at this time, the upper check valve 74 closes, andthe backward flow of gas can be restricted.

Next, the lower partitioning wall 62 is provided within the side airbag16, and divides the lower chamber 76 and the intermediate chamber 80,and divides the lower chamber 76 and the initially inflated portion 68.This lower partitioning wall 62 is provided within the side airbag 16 byend edges 62A at bag thickness direction both sides respectively beingsewn to the base cloth 58 that faces in the bag thickness direction(sewn portions S18).

The lower check valve 64 is provided at a partial region of the lowerpartitioning wall 62, and, for example, is provided at the seat rear endportion where the inflator 18 is positioned. The lower check valve 64 isprovided convexly toward the lower chamber 76 side when the side airbag16 is not inflated and expanded, and is structured so as to permitflowing of gas for inflation from the initially inflated portion 68 sideto the lower chamber 76 side and restrict gas flowing in the directionopposite thereto. The structure and the operational principles of thelower check valve 64 are similar to the upper check valve 74.

The intermediate partitioning wall 66 is provided within the side airbag16 so as to divide the initially inflated portion 68 and theintermediate chamber 80, and an air hole 66B, that permits the inflow ofgas from the initially inflated portion 68 to the intermediate chamber80, is provided therein. This intermediate partitioning wall 66 isprovided within the side airbag 16 due to end edges 66A at the bagthickness direction both sides respectively being sewn to the base cloth58 that faces in the bag thickness direction (sewn portions S19). Theopening surface area of the air hole 66B provided in the intermediatepartitioning wall 66 is set to be lower than the opening surface area ofthe upper check valve 74 and the opening surface area of the lower checkvalve 64. This is so that gas is preferentially supplied to the lowerchamber 76 and the upper chamber 78 when the side airbag 16 inflates andexpands.

Note that, as shown in FIG. 29, FIG. 30, the upper partitioning wall 72and the lower partitioning wall 62 are formed so as to be bentappropriately as seen in a side view of the seat, in order to make thepositions and the volumes of the lower chamber 76, the upper chamber 78,the intermediate chamber 80, and the initially inflated portion 68appropriate. The bent shapes of the upper partitioning wall 72 and thelower partitioning wall 62 are not limited to the illustrated shapes.

(Operation)

The present embodiment is structured as described above, and theoperation thereof is described hereinafter. In FIG. 29, at the sideairbag device 60 relating to the present embodiment, the lower checkvalve 64 is provided at a partial region of the lower partitioning wall62, and the upper check valve 74 is provided at a partial region of theupper partitioning wall 72. Therefore, as compared with a structure inwhich the respective check valves are provided separately from therespective partitioning walls, costs required for sewing the side airbag16 is reduced, and smaller size and lighter weight of the package formedby folding-up the side airbag 16 can be devised.

Further, in FIG. 30, at the time of a side collision, the inflator 18operates, and the gas for inflation that is jetted-out from the inflator18 is first supplied to the initially inflated portion 68. This gasfurther is supplied from the initially inflated portion 68 to the lowerchamber 76 through the lower check valve 64.

Due to the upper check valve 74 opening due to the pressure of gaswithin this initially inflated portion 68, gas within the initiallyinflated portion 68 is supplied in the arrow B direction to the upperchamber 78 through the upper check valve 74. Further, due to the lowercheck valve 64 opening due to the pressure of gas within the initiallyinflated portion 68, gas within the initially inflated portion 68 issupplied in the arrow A direction to the lower chamber 76 through thelower check valve 64. Moreover, gas within the initially inflatedportion 68 is supplied to the intermediate chamber 80 through the airhole 66B of the intermediate partitioning wall 66.

When jetting-out of gas from the inflator 18 ends, gas attempts to flowbackward from the lower chamber 76 and the upper chamber 78 to theinitially inflated portion 68. However, because the lower check valve 64and the upper check valve 74 restrict this flow of gas, the internalpressure of the lower chamber 76 and the internal pressure of the upperchamber 78 can respectively be maintained in high pressure states.

On the other hand, because the backward flow of gas from theintermediate chamber 80 to the initially inflated portion 68 ispermitted, the internal pressure of the intermediate chamber 80 can bemade to be relatively low pressure. Therefore, the chest portion 32C ofthe passenger 32 can be restrained appropriately by this intermediatechamber 80.

Note that, in the above-described respective embodiments, the diffuser34 is formed by using the diffuser base cloth 35, but the diffuser 34 isnot limited to a diffuser made of cloth, and, for example, may be adiffuser made of metal. Further, a vent hole, for further reducing theinternal pressure at the time of restraining the passenger, may beprovided in the low pressure chamber at the side airbag 16.

DESCRIPTION OF THE REFERENCE NUMERALS

-   10 side airbag device-   12 vehicle seat-   16 side airbag-   18 inflator-   20 side airbag device-   22 partitioning wall-   24 check valve-   26 lower chamber (high pressure chamber)-   26A bottom portion-   27 lower base cloth (base cloth that forms high pressure chamber)-   27C end edge positioned at peripheral edge portion of high pressure    chamber-   27D end edge positioned at central portion of partitioning wall-   28 upper chamber (low pressure chamber)-   29 upper base cloth (base cloth that forms low pressure chamber)-   29C end edge of base cloth that forms low pressure chamber-   30 side airbag device-   32 passenger-   32C chest portion-   32S shoulder portion-   32W waist portion-   34 diffuser-   34D lower opening portion (main opening portion)-   34U upper opening portion (auxiliary opening portion)-   34F front opening portion-   35 diffuser base cloth (base cloth that forms diffuser)-   36 intermediate chamber (low pressure chamber)-   37 central base cloth (base cloth that forms intermediate chamber)-   37E end edge that runs along length direction of diffuser-   38 upper chamber (high pressure chamber)-   38A bottom portion-   39 upper base cloth (base cloth that forms high pressure chamber)-   39C end edge positioned at peripheral edge portion of high pressure    chamber-   39U end edge positioned at central portion of partitioning wall-   40 side airbag device-   42 lower partitioning wall-   44 lower check valve-   50 side airbag device-   52 upper partitioning wall-   55 upper check valve-   56 overlapping region-   58 base cloth-   58C peripheral edge portion-   60 side airbag device-   62 lower partitioning wall-   64 lower check valve-   66 intermediate partitioning wall-   66B air hole-   68 initially inflated portion-   72 upper partitioning wall-   74 upper check valve-   76 lower chamber-   78 upper chamber-   80 intermediate chamber

The invention claimed is:
 1. A side airbag device comprising: a sideairbag that inflates and expands at a time of a side collision, and thathas a high pressure chamber that becomes a high pressure side at a timeof inflation and expansion, and a low pressure chamber that becomes alower pressure than the high pressure chamber, the high pressure chamberand the low pressure chamber being formed by base cloths that arerespectively separate bodies; an inflator that supplies gas forinflation into the side airbag; a partitioning wall that is formed by aportion of a base cloth that forms the high pressure chamber, and thatdivides the high pressure chamber and the low pressure chamber; and acheck valve that is provided at a partial region of the partitioningwall, and that is provided convexly toward the high pressure chamberside when the side airbag is not inflated, and that permits flowing ofthe gas for inflation from the low pressure chamber side to the highpressure chamber side, and restricts flowing of gas in a directionopposite thereto, wherein the base cloth that forms the high pressurechamber is folded in two convexly toward the high pressure chamber sideat a region that becomes a central portion of the partitioning wall, andis further folded-over respectively toward a bag outer side and the highpressure chamber side at both end portions in a bag thickness directionof a region that becomes the partitioning wall, and end edges that arepositioned at a peripheral edge portion of the high pressure chamber aresewn together.
 2. The side airbag device of claim 1, wherein, at theside airbag in an inflated and expanded state, the high pressure chamberis a lower chamber that corresponds to a waist portion of a passengerseated in a vehicle seat, and the low pressure chamber is an upperchamber that corresponds to at least one of a chest portion or ashoulder portion of the passenger.
 3. The side airbag device of claim 2,comprising: a diffuser that guides the gas for inflation mainly to thelower chamber side, and also guides the gas for inflation to the upperchamber side, wherein the diffuser has a main opening portion that opensto the lower chamber side, and an auxiliary opening portion that opensto the upper chamber side.
 4. The side airbag device of claim 3, whereina base cloth that forms the diffuser is sewn together with a base cloththat forms the low pressure chamber at at least a peripheral edgeportion of the low pressure chamber, and is formed in a form of a tube.5. A method of sewing a side airbag, the side airbag having a highpressure chamber that becomes a high pressure side at a time ofinflation and expansion, and a low pressure chamber that becomes a lowerpressure than the high pressure chamber, and in which the high pressurechamber and the low pressure chamber are formed by base cloths, that arerespectively separate bodies, and are divided by a partitioning wall,and in which the partitioning wall is formed by a portion of a basecloth that forms the high pressure chamber, the method comprising: astep of forming, at a partial region of the partitioning wall, a checkvalve that permits flowing of gas for inflation from the low pressurechamber side to the high pressure chamber side, and restricts flowing ofthe gas in a direction opposite thereto; a step of folding the basecloth that forms the high pressure chamber in two convexly toward thehigh pressure chamber side at a region that becomes a central portion ofthe partitioning wall, and sewing both end portions in a bag thicknessdirection of a region that becomes the partitioning wall to a base cloththat forms the low pressure chamber; and a step of folding-over the basecloth that forms the high pressure chamber, respectively toward a bagouter side and the high pressure chamber side at both end portions inthe bag thickness direction of the region that becomes the partitioningwall, and, at a peripheral edge portion of the high pressure chamber,sewing together end edges of the base cloth that forms the high pressurechamber, and, at a peripheral edge portion of the low pressure chamber,sewing together end edges of the base cloth that forms the low pressurechamber.